# How can I find the horizontal intercept of the equation #y=-4x^2-8x+12# algebraically?

##### 2 Answers

The horizontal intercepts have coordinates

#### Explanation:

We want to find the intercepts of a certain graph with the

This means that a point on the graph is on the

Since

or, if you prefer,

note that the whole equation can be simplified dividing by

To solve this equation, you can either use the quadratic formula, or look for two number that give

The second request is satisfied only by

x-intercepts:

y-intercept:

#### Explanation:

I assume by "horizontal" you mean the x-intercept?

To find the x-intercept set

Factor:

To find the y-intercept set

as you can. see by what we, with did any quadratic function:

the y-intercept is just

graph{y=-4x^2-8x+12 [-20.71, 19.29, -3.68, 16.32]}